This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This study is designed to evaluate the protective potential of the HIV-1 regulatory protein, Tat, as a purified biologically active protein (Tatwt protein) and as a gene product expressed by a recombinant replication-competent adenovirus vector (Ad5hr-HIVtatwt) in Macaca fascicularis of Mauritius origin. Two groups of nine macaques each received nine (weeks 0, 2, 6, 11, 15, 21, 28, 32, and 36) subcutaneous and intradermal vaccinations with Tat protein (Group 1) or two vaccinations, one intranasal (week 0) and the other intratracheal (week 12) with Ad5hr-HIVtat, plus two boosts with Tat protein (Group 2) at weeks 24 and 36. Two groups of three macaques that received alum only (Group 4) or empty vector (Group 3) serve as controls. Immune responses were assayed by ELISA, Luminex multianalyte profiling (xMAP), T-cell IFN-[unreadable] ELISPOT, intracellular cytokine staining, proliferation assays and HIV neutralization on blood obtained prior to, at the time of, and two weeks following each immunization. Mucosal secretions (rectal and nasal swabs and saliva) were assayed by xMAP. The xMAP system is being evaluated in comparison to the standard Tat ELISA.